In addition to using a logarithmic scale on the y-axis to generate what is commonly known as a 'lin-log' scale it is also possible to use a logarithmic scale on the x-axis to get a 'log-log' plot (as is often used in electrical engineering). An example of this is shown in Figure 14.61. The log board feet calculator utilizes log rules calculations. By entering in the diameter inside the bark at the small end and the length, the scaling techniques for International, Doyle, and Scribner are calculated and shown on the screen. Anti-logarithm calculator. In order to calculate log-1 (y) on the calculator, enter the base b (10 is the default value, enter e for e constant), enter the logarithm value y and press the = or calculate button. Every log in every load (1-in-1, or 100%) can be scaled, or any one of a number of approved sampling methods can be used, such as scaling a portion of the loads, 3P scaling, or sample weight scaling. Another method being used more frequently is weight scaling, especially on low value material where there is a single species/product, or where.

• Download Linear To Log Scale Conversion For Android Pdf
• Convert To Log Scale
• Convert Log Scale To Linear
• Download Linear To Log Scale Conversion For Android

A logarithmic, or log, scale gives equal visual weight to equal relative changes: a 10% move looks the same whether it is from a high or a low base.

The result is that the magnitudes of earlier and later booms and busts can be compared on a level playing field. In the case of the Dow Jones since 1900, information in the first half of the chart has now been fully brought to light. Further, with log scales, series experiencing exponential growth appear as straight lines, making charts easier to interpret.

Finally, the use of nominal prices absolves researchers of the need to select a deflator and deal with the theoretical issues such a choice would entail. Researchers are often still interested in inflation as one economic phenomenon among many, and they can incorporate that into charts separately. But for a quick summary of a market, there is value in plotting raw price data.

It is worth noting that, for all their advantages, log scale charts have at least one failing: they cannot show negative values, even though prices can fall below zero. Indeed, this regularly occurs in European power markets. Separately, natural gas has tradedas low as -$.29 MMBTU on a North American market amid transportation capacity constraints.

Other complications with log scales can occur with axis labelling. Most charting software automatically labels logarithmic axes with exponentially increasing values: for example, 10^0, 10^1, 10^2, and so on. In time series with meaningful units – such as exchange rates, bond prices and commodity prices - these are not the increments that are most relevant to investors. For instance, on an oil chart, we may want to label in multiples of $25 per barrel. To do this, we need to turn to more flexible charting technologies.

Crude Oil – Logarithmic Chart with Custom Labels

In all the previous discussion we have used linear scales. Another option is to use a logarithmic scale. This is often used when there is a need to display both very small and very large values in the same graph. The library supports the use of logarithmic scales on both the x- and y-axis (as well as the optional extra y-axis).

The logarithmic scale support is defined in the module file 'jpgraph_log.php' so this must be included in order to access this feature.

To illustrate the use of a logarithmic scale we will make a graph which uses two y-axis and make the second y-axis have a logarithmic scale (we will actually take the graph in Figure 15.16. Adding and adjusting the position of the legend box (example6.php) and change the second y-axis to be a logarithmic scale instead).

In order to use a logarithmic scale on the second (Y2) axis we only need to change

to

and the library will take care of the rest. The result of this is shown in Figure 14.59. Changing the Y2 scale from linear to logarithmic (example7.php)

Figure 14.59. Changing the Y2 scale from linear to logarithmic (example7.php)

By default only the major grid lines on the y-axis are shown. By adding the lines

We can enable both the x-grid lines as well as the minor grid lines on the y-axis to get the result shown in Figure 14.60. Enabling minor grid lines on the y-axis and also grid lines on the x-axis (example8.php) below

Figure 14.60. Enabling minor grid lines on the y-axis and also grid lines on the x-axis (example8.php)

In addition to using a logarithmic scale on the y-axis to generate what is commonly known as a 'lin-log' scale it is also possible to use a logarithmic scale on the x-axis to get a 'log-log' plot (as is often used in electrical engineering). An example of this is shown in Figure 14.61. An example of a log-log plot (where both the y- and x-axis use a logarithmic scale) (loglogex1.php)

Figure 14.61. An example of a log-log plot (where both the y- and x-axis use a logarithmic scale) (loglogex1.php)

Note

The example in Figure 14.61. An example of a log-log plot (where both the y- and x-axis use a logarithmic scale) (loglogex1.php) also makes use of scatter plots which we have not yet introduced but is a way to draw a plot of a number of data points specified by both there x- and y-coordinates.

Tip

If you think the first value of the Y-axis is to close to the first label of the X-axis you have the option of either increasing the margin (with a call to SetLabelMargin() ) or to hide the first label (with a call to Axis::HideFirstTickLabel() )

As a final example of using a logarithmic scale we show how to combine a text scale for the x-axis and a logarithmic scale for the y-axis. As we already shown in Graphing the number of sun spots during the 19th Century it is possible to manually specify the labels that should be used on the axis with a call to Axis::SetTickLabels(). Let's make use of this and the built-in library super global variable '$gDateLocale' which is an instance of a date utility class to get a list of the name of all the months in a localized fashion.

To use the name of the months on the x-axis we haev to add the following two lines to the previous example

The result of adding these two lines are shown in Figure 14.62. Using a text-log scale (example9.php) below

Figure 14.62. Using a text-log scale (example9.php)

Since the name of the months are quite close we can change what labels should be displayed as was discussed in Manually specifying scale labels to only show every second label. Doing this change gives the result shown in Figure 14.63. Adjusting the text scale so that only every second labels are displayed. (example9.1.php)

Figure 14.63. Adjusting the text scale so that only every second labels are displayed. (example9.1.php)

Download Linear To Log Scale Conversion For Android Pdf

Another option if we think that the labels are too close is to rotate them. In Figure 14.64. Rotating the x-axis labels 90 degree (example9.2.php) we have kept all labels but rotated them 90 degree.

Figure 14.64. Rotating the x-axis labels 90 degree (example9.2.php)

Convert To Log Scale

Caution

Convert Log Scale To Linear

Download Linear To Log Scale Conversion For Android

Remember that the built-in bitmap fonts only supports 0 and 90 degree text. TTF fonts support texts at an arbitrary angle.